In the minimum I got 6db improvement, it depends also on the output
impedance and layout of the components.
I gained 10db more at high output impedance.
Most are 1000-1500 ohms, 160m is 3 kohm.
Before I used simple Pi, but for SO2R M/M operation I converted them all.
Vacuum output capacitors were used already except on the 160m amp, no padder
anymore.
Usually the Pi-coil is above the chassis, the L is below it together with
the load cap.
In the 160m amp both coils are above chassis but 90 degrees to each other
and there the difference is very remarable.
The middle impedance on the lower z amps is 600-800 ohms and I am using 1200
ohms on the 160m amp.
Antennas are monoband as well.
M/M is possible while antennas are 3m apart on the same mast.
I tried Pi-L on a new built multiband amp but gave up and went to Pi again,
to many problems with arcs in the bandswitch.
73
Peter
-----Original Message-----
From: Tom W8JI [mailto:w8ji@w8ji.com]
Sent: Donnerstag, 29. März 2007 01:04
To: Peter Voelpel; amps@contesting.com
Subject: Re: [Amps] Pi-L Network
> Would be very interesting.
> And the Pi-L IS better then the Pi on harmonic suppression.
> I use it in all my monoband amps.
So how many dB better is it into your actual antennas?
What middle impedance do you use?
Do you partition or shield the L coil from the main tank coil and tube
leads??
73 Tom
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